Behavioural and energetic consequences of competition among three overwintering swan (Cygnus spp.) species
Funder: Peter Scott Trust for Education and Research in Conservation Funder: Peter Smith Charitable Trust for Nature Funder: Olive Herbert Charitable Trust Funder: D’Oyly Carte Charitable Trust Funder: N. Smith Charitable Settlement Funder: Robert Kiln Charitable Trust Funder: The estate of the late...
| Main Authors: | , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Elsevier BV
2021
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| Subjects: | |
| Online Access: | https://www.repository.cam.ac.uk/handle/1810/328378 https://doi.org/10.17863/CAM.75827 |
| Summary: | Funder: Peter Scott Trust for Education and Research in Conservation Funder: Peter Smith Charitable Trust for Nature Funder: Olive Herbert Charitable Trust Funder: D’Oyly Carte Charitable Trust Funder: N. Smith Charitable Settlement Funder: Robert Kiln Charitable Trust Funder: The estate of the late Professor Geoffrey Matthews OBE <jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>Winter numbers of the northwest European population of Bewick’s Swans (<jats:italic>Cygnus columbianus bewickii</jats:italic>) declined recently by c. 40%. During the same period, numbers of two sympatric and ecologically-similar congeners, the Mute Swan (<jats:italic>Cygnus olor</jats:italic>) and Whooper Swan (<jats:italic>Cygnus cygnus</jats:italic>) showed increases or stability. It has been suggested that these opposing population trends could have a causal relationship, as Mute and Whooper Swans are larger and competitively dominant to Bewick’s Swans in foraging situations. If so, effects of competition of Mute and Whooper Swans on Bewick’s Swans should be detectable as measurable impacts on behaviour and energetics.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Here, we studied the diurnal behaviour and energetics of 1083 focal adults and first-winter juveniles (“cygnets”) of the three swan species on their winter grounds in eastern England. We analysed video recordings to derive time-activity budgets and these, together with estimates of energy gain and expenditure, were analysed to determine whether individual Bewick’s Swans altered the time spent on key behaviours when sharing feeding habitat with other swan species, and any consequences for their energy expenditure and net energy gain.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>All three swan species spent a small proportion of their ... |
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